Exercise Optionals 02

Author: SteffenLm

.github/workflows/format.yml

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+name: format and commit all java files
+
+on:
+  workflow_dispatch:
+  push:
+    branches:
+      - 'exercises/**'
+      - 'solutions/**'
+
+jobs:
+  formatting:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-java@v3
+        with:
+          java-version: '17'
+          distribution: 'temurin'
+      - uses: axel-op/googlejavaformat-action@v3

.gitignore

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+# Compiled class file
+*.class
+
+# Log file
+*.log
+
+# BlueJ files
+*.ctxt
+
+# Mobile Tools for Java (J2ME)
+.mtj.tmp/
+
+# Package Files #
+*.jar
+*.war
+*.nar
+*.ear
+*.zip
+*.tar.gz
+*.rar
+
+# virtual machine crash logs, see http://www.java.com/en/download/help/error_hotspot.xml
+hs_err_pid*

Exercise.java

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+public class Exercise {
+
+  public static void main(String[] args) {
+    TelephoneBook telephoneBook = new TelephoneBook();
+
+    telephoneBook.addEntry(
+        new TelephoneBook.Person("Hans Maier"),
+        new TelephoneBook.TelephoneNumber("+49 67234 887261"));
+    telephoneBook.addEntry(
+        new TelephoneBook.Person("Peter Mueller"),
+        new TelephoneBook.TelephoneNumber("+49 7529 87612"));
+    telephoneBook.addEntry(
+        new TelephoneBook.Person("Lisa Schmidt"),
+        new TelephoneBook.TelephoneNumber("+49 8762 52081"));
+
+    System.out.println(telephoneBook.getTelephoneNumberByName("Hans Maier"));
+  }
+}

TelephoneBook.java

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+import java.util.HashMap;
+import java.util.Map.Entry;
+
+public class TelephoneBook {
+
+  private HashMap<Person, TelephoneNumber> entries = new HashMap<>();
+
+  public void addEntry(Person person, TelephoneNumber telephoneNumber) {
+    entries.put(person, telephoneNumber);
+  }
+
+  public TelephoneNumber getTelephoneNumberByName(String name) {
+    for (Entry<Person, TelephoneNumber> entry : entries.entrySet()) {
+      if (entry.getKey().name().equals(name)) {
+        return entry.getValue();
+      }
+    }
+    return null;
+  }
+
+  public record Person(String name) {}
+
+  public record TelephoneNumber(String value) {}
+}